Processing

Please wait...

Settings

Settings

Goto Application

1. WO2016144645 - CEMENT SPACER SYSTEM FOR WELLBORES, METHODS OF MAKING, AND METHODS OF USE

Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

[ EN ]

CLAIMS

1. A cement spacer fluid for use in a wellbore, comprising

an aqueous cement spacer carrier fluid; and

a preformed synthetic polymer swellable in the aqueous cement spacer carrier fluid in an amount effective to displace a drilling fluid during a cementing operation.

2. The cement spacer fluid of claim 1, wherein the carrier fluid comprises fresh water, salt water, aqueous acid, aqueous base, or a combination comprising at least one of the foregoing.

3. The cement spacer fluid of any one or more of claims 1 to 2, wherein the preformed synthetic polymer is stable up to about 350°F.

4. The cement spacer fluid of any one or more of claims 1 to 3, wherein the preformed synthetic polymer comprises poly(hydroxyCi_8 alkyl (meth)acrylate) such as poly(2 -hydroxy ethyl acrylate), poly(Ci_8 alkyl (meth)acrylate), poly(meth)acrylamide, poly(vinyl pyrrolidine), poly( vinyl acetate), or a combination comprising at least one of the foregoing polymers,

5. The cement spacer fluid of any one or more of claims 1 to 4, wherein the preformed synthetic polymer comprises

a homopolymer of (meth)acrylamide or a copolymer of (meth)acrylamide with maleic anhydride, vinyl acetate, ethylene oxide, ethylene glycol, acrylonitrile, or a combination comprising at least one of the foregoing;

poly(acrylamide) having crosslinks derived from polyethylene glycol diacrylate; poly(acrylic acid) having crosslinks derived from a vinyl ester oligomer; or a poly(acrylic acid) partial sodium salt-graft-poly(ethylene glycol).

6. The cement spacer fluid of any one or more of claims 1 to 5, wherein the preformed synthetic polymer is present in the form of particles, preferably swelled particles, comprising the polymer.

7. The cement spacer fluid of any one or more of claims 1 to 6, wherein the particles are swelled and at least about 50% of the polymer particles have an average largest diameter of about 500 to about 12,000 micrometers, preferably about 1,000 to about 10,000 micrometers, more preferably about 2,000 to about 8,000 micrometers.

8. The cement spacer fluid of any one or more of claims 1 to 7, wherein the preformed synthetic polymer is present in the cement spacer fluid in a concentration of about 1 pound to about 200 pounds per thousand gallons of aqueous cement spacer carrier fluid, preferably about 10 pounds to about 100 pounds of aqueous cement spacer carrier fluid, more preferably about 30 pounds to about 60 pounds of aqueous cement spacer carrier fluid.

9. The cement spacer fluid of any one or more of claims 1 to 8, further comprising guar, carrageenan, or a combination comprising at least one of the foregoing.

10. The cement spacer fluid of any one or more of claims 1 to 9, wherein the preformed synthetic polymer is present in the form of a hydrated pack of swelled polymer particles.

11. A method of cementing a wellbore comprising a drilling fluid, the method comprising

injecting the cement spacer fluid of any one or more of claims 1 to 10 into the wellbore to displace the drilling fluid;

injecting a cement slurry into the wellbore subsequent to injecting the cement spacer fluid; and

hardening the cement in the slurry to cement the wellbore.

12. The method of claim 11, wherein displacing the drilling fluid further comprises displacing a contaminant particulate present in the wellbore.

13. The method of claim 12, wherein the contaminant particulate comprises a drilling fluid particulate, drilling cutting, a reservoir rock particulate such as a shale particulate, mudstone particulate, sandstone particulate, carbonate particulate, or a combination comprising at least one of the foregoing.

14. The method of any one or more of claims to 11 to 13, wherein the cement spacer fluid is a first cement spacer fluid, and the method further comprises injecting a second spacer fluid into the well bore after the first spacer fluid and before the cement slurry.

15. The method of any one or more of claims 11 to 14, wherein the wellbore is a vertical or horizontal wellbore.